Waterflood employing a viscoelastic, shear-hardening, positive nonsimple liquid with stabilizing agent
A soap system containing two types of stabilizing agents was effective for secondary oil recovery. The soap system was an aqueous flood containing sodium oleate, 1 percent sodium chloride, sodium hydroxide, sodium Versenate (the tetra-sodium salt of ethylenediaminetetraacetic acid), 2-ethylhexanol, and benzene. The 2-ethylhexanol and benzene were the stabilizing agents. Sodium Versenate, a chelating agent, was added to the flood to prevent formation of the calcium soap. The surfactant flood should contain no more than 100 ppm of divalent cations. Cores of Yates sand, Kermit Field, Winkler County, Texas (41.02 percent porosity, 577 md permeability) were saturated with water, flooded with Yates crude oil (4.4 cp viscosity), waterflooded, and reflooded with Yates crude before treatment with the surfactant flood. A maximum recovery of 88.4 percent OOIP was obtained using both stabilizing agents. A preflush of 2-ethylhexanol in water followed by the flood of the soap system containing only one stabilizing agent (2-ethylhexanol) gave a higher recovery, 95.2 percent OOIP. Use of only 2-ethylhexanol in the flood, without the preflush, recovered only 72.5 percent OOIP.
- Assignee:
- Mobil Oil Corp.
- Patent Number(s):
- US 3410343
- OSTI ID:
- 7215922
- Country of Publication:
- United States
- Language:
- English
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